Sierra Gearcase Filler Valve 18-99528, Replaces CDI Electronics 551-33VA / 551-33-1

The Sierra 18-99528 is a replacement gearcase filler valve built for marine gear oil change and fill pump systems. It is a single-port globe valve molded in blue plastic, with a solvent-weld inlet connection and a flange outlet connection, making it a straightforward drop-in replacement where the original filler valve has worn out, cracked, or started to leak. The valve is designed for use in a marine environment, so it stands up to the moisture and exposure typical around a boat's gear oil filling system.

This part is a direct equivalent to CDI Electronics 551-33VA and is used with the 551-33-1 gearcase filler assembly, letting you replace just the valve component rather than the entire filler unit. At 0.1 pounds, it is a light, compact component intended for straightforward removal-and-replacement service rather than a full system rebuild.

Specifications

• Brand: Sierra
• Manufacturer Part Number: 18-99528
• OEM Cross Reference: 551-33va, 551-33-1
• Material: Plastic
• Color: Blue
• Valve Type: Globe Valve
• Inlet Connection Type: Solvent
• Outlet Connection Type: Flange
• Number of Ports: 1
• Weight: 0.1 pounds
• UPC: 808282394769

Fitment

Designed for use with the 551-33-1 gearcase filler assembly.

Replaces (OEM)

• 551-33va
• 551-33-1

Frequently Asked Questions

What is the Sierra 18-99528 used for? The Sierra 18-99528 is a gearcase filler valve used in marine gear oil change and fill pump systems, replacing the valve component when the original has failed.

Is the Sierra 18-99528 the same as the CDI Electronics 551-33VA? Yes, the Sierra 18-99528 is a direct equivalent to CDI Electronics 551-33VA and can be used in place of it.

What does the Sierra 18-99528 fit? This valve is designed for use with the 551-33-1 gearcase filler assembly.

What material is the Sierra 18-99528 valve made from? It is made from plastic, molded in blue, and designed for use in a marine environment.

What type of valve is the Sierra 18-99528? The 18-99528 is a single-port globe valve.

What connections does the Sierra 18-99528 use? It has a solvent-weld inlet connection and a flange outlet connection.

How much does the Sierra 18-99528 weigh? The 18-99528 gearcase filler valve weighs 0.1 pounds.

Does the Sierra 18-99528 include any other parts? The 18-99528 is the replacement valve itself; it does not include the full 551-33-1 gearcase filler assembly.

Can I use the Sierra 18-99528 to replace just the valve instead of the whole filler assembly? Yes, the 18-99528 is intended as a replacement valve so you can service the 551-33-1 gearcase filler without replacing the entire assembly.

Is the Sierra 18-99528 an aftermarket or genuine equivalent part? The 18-99528 is sold under the Sierra part number as a direct equivalent to the CDI Electronics 551-33VA valve.